A grim-looking Pepe declared in a video on Real TV that the incident during Real Madrid's 2-1 defeat in the Spanish Cup quarter-final clash at the Santiago Bernabeu Wednesday was not deliberate.

"It was an unintentional act. All the same, if Messi was offended then I apologise to him," the 28-year-old defender said.

"All I mean to do is defend my team and my institution. I give myself to it body and soul. It never crosses my mind to hurt a fellow professional," Pepe added.

Television images of the clash showed Pepe walking towards the referee, glancing down quickly at Messi, who was lying on the ground, and then stamping on his left hand with his boot.

"He deceives, he stamps and on top of it all he lies," said the front page of Barcelona-based daily Sport.

An opinion piece in Spain's biggest-selling sports daily Marca, added: "If Pepe was trying to get a minimum of sympathy on Real TV for his stamp on Messi, he achieved the opposite. Describing as 'involuntary' an act that the whole world saw is another serious act of rashness."

They included an incident from a league match against Getafe in April 2009 when Pepe shoved Francisco Casquero to the ground and stamped him several times, then palmed another player in the face and insulted the referee, earning a 10-match ban.

France great and current Real Madrid director of football Zinedine Zidane came to Pepe's defence in an interview with sports daily As.

"He is a charming, polite guy. But when he gets on to the pitch he is obsessed with victory and that anxiousness to win makes him commit errors.

"Of course he regrets what he did but Pepe is a player who gives everything on the pitch to win. And sometimes he brushes the limits," said Zidane.

Zidane defended Real Madrid boss Jose Mourinho over the Barcelona loss, saying the Portuguese coach was building a stronger team. To accept calls to change the coach would be "crazy," he said.

"I challenge all the coaches of the world to say what is the right system to beat Barca," Zidane said.